The present invention relates to arcuate-winged submersible vehicles for use in, for example, underwater payload delivery and data acquisition, including hydrographic surveys for commercial, ecological, professional, or recreational purposes.
Submersible vehicles are presently used for a wide variety of underwater operations, including inspection of telephone lines and pipe lines, exploration for natural resources, performance of bio-mass surveys of marine life, inspection of hulls of surface vessels or other underwater structures, and to search for shipwrecks and sunken relics. Submersible vehicles may be manned or unmanned, and may carry a wide variety of payloads. Furthermore, submersible vehicles may be towed by a surface vessel, or may be equipped with a propulsion unit for autonomous mobility. Overall, submersible vehicles are an important tool in the performance of a wide variety of hydrographic surveys for commercial, ecological, professional, or recreational purposes.
FIG. 1 shows a towed submersible vehicle 10 and related support equipment in accordance with the prior art. In this embodiment, the submersible vehicle 10 includes a hull 12 having a streamlined cylindrical body 13. Several fins 14 project radially from the hull 12 as fixed control surfaces. The front (or bow) of the body 13 includes an open aperture 16 covered by a transparent window 18. The body 13 has a substantially enclosed back (or stern) 20 and a tail section 22 which is attached to the back 20 and which has a vertical steering flap 24 and a horizontal steering flap 26. The vertical and horizontal steering flaps 24, 26 are actuated by a pair of actuators (not shown) which are disposed within a payload area 21 inside the body 13. Actuator arms 28 extend through the back 20 of the hull 12 to actuate the vertical and horizontal steering flaps 24, 26.
The hull 12 also includes a tow point 30 located on an upper portion of the body 13 for attaching the submersible vehicle 10 to a tether or tow cable of a surface vessel. A pair of runners 32 are attached to the lower fins 14 to protect the vehicle from striking rocks or other objects on the ocean floor.
Support equipment for the submersible vehicle 10 includes a control unit 34, which is connected to the submersible vehicle 10 by an umbilical 36. Power is delivered to the submersible vehicle 10 through the umbilical 36, and control signals from the controller 34 are transmitted through the umbilical 36 to the actuators for independently actuating the vertical steering flap 24 and the horizontal steering flap 26. In the embodiment shown in FIG. 1, a viewing visor 38 may be connected by the umbilical 36 to a camera located within the payload compartment 21 which transmits photographic images of the underwater scene to the viewing visor 38. A camera control box 40 is electronically coupled to the camera by the umbilical 36, enabling an operator on the surface vessel to adjust the photographic images as desired.
In operation, the submersible vehicle 10 is towed behind a surface vessel over an area of interest, such as a pipeline, potential fishing area, or potential shipwreck area. Wearing the viewing visor 38, the operator uses the controller 34 to control the movement of the submersible vehicle by adjusting the deflections of the vertical and horizontal steering flaps 24, 26. Lateral movement of the submersible vehicle 10 is controlled by deflecting the vertical steering flap 24, causing the vehicle to turn to the right or left (i.e. xe2x80x9cyawxe2x80x9d). The depth of the submersible vehicle 10 is controlled by deflecting the horizontal steering flap 26, causing the bow of the vehicle to pitch up or down (i.e. xe2x80x9cpitchxe2x80x9d). In this way, the operator is able to control the flight of the submersible vehicle 10 over the areas of interest on the ocean floor to perform inspections or acquire desired information.
Although desirable results have been achieved using the prior art system, several characteristics of the submersible vehicle 10 leave room for improvement. For instance, when the vehicle 10 is being towed in a current, especially a current that flows across the direction of travel of the surface vessel, the submersible vehicle 10 may become unstable. Cross-currents tend to cause the submersible vehicle 10 to xe2x80x9crollxe2x80x9d about a lengthwise axis so that the runners 32 may no longer remain below the vehicle for protection. The rolling of the submersible vehicle 10 may also interfere with or disable the data acquisition equipment contained within the payload section. Strong currents along the direction of travel of the surface vessel (i.e. along the freestream flow direction) may also hamper the controllability of the vehicle 10.
Also, undesirable rolling characteristics are experienced when the submersible vehicle 10 is guided by the operator to a position that is laterally displaced to the sides of the surface vessel. That is, when the submersible vehicle 10 is flown out widely to the left or to the right of the surface vessel, the tether which is attached to the tow point 30 pulls on the tow point causing the vehicle to roll undesirably.
Furthermore, under some operating conditions, the shape and orientation of the fins 14 and the vertical and horizontal steering flaps 24, 26 fail to provide the desired hydrodynamic stability and controllability of the submersible vehicle 10. In rough seas and high currents, such as those which may be experienced in the fisheries of the North Atlantic and North Pacific Oceans, and in some areas commonly associated with shipwrecks in the southeastern Pacific Ocean, prior art submersible vehicles sometimes fail to provide adequate or required stability or maneuverability characteristics, including roll, pitch, and yaw control.
The present invention relates to arcuate-winged submersible vehicles with improved stability and maneuverability characteristics. In one embodiment, a vehicle includes a body having a pair of outwardly projecting at least partially arcuate wings, an adjustably positionable wing steering flap hingeably attached to each wing to provide at least partial control of the movement of the vehicle, at least one wing flap actuator coupled to the hull and to the wing steering flaps to controllably adjust the position of the wing flaps, a tail attached to the hull having an adjustably positionable hingeable tail steering flap to provide at least partial control of the movement of the vehicle, and at least one tail flap actuator coupled to the hull and to the tail steering flap to controllably adjust the position of the tail steering flap. The arcuate wings provide improved stability and maneuverability characteristics of the vehicle.
In alternate embodiments, a vehicle may include arcuate wings having a swept leading edge or a swept trailing edge, or both. Alternately, a vehicle may have arcuate wings each having a trailing edge with a substantially planar and a cutout area disposed therein, the wing steering flaps being attached to the arcuate wings and received within the cutout areas. In another embodiment, each arcuate wing has a rearwardly swept leading edge and a forwardly swept trailing edge that joins with the leading edge at a wing tip, and a ratio of a wingspan over a maximum distance from the leading edge to the trailing edge is approximately 3/2. In a further embodiment, each arcuate wing has a wing tip and a wing root attached to the hull, and the curvature of each arcuate wing is such that the wing tip is at approximately the same water line as the wing root.
In yet another embodiment, a vehicle has a tow assembly attached to the hull and coupleable with a tow cable for towing the vehicle behind a surface vessel or for launching and recovery of the vehicle. Alternately, the tow assembly may have an outwardly projecting tow plate hingeably attached to the hull and approximately aligned with a longitudinal axis of the hull, with the tow plate having an at least partially arcuate slot sized to receive and slideably guide a towing device disposed therein.
In still another embodiment, a vehicle includes a propulsion unit attached to the hull for propelling the vehicle through a fluid medium. In an alternate embodiment, a vehicle has a control unit operatively coupled to at least one actuator, the control unit providing a control signal to actuate the actuator to adjust a position of at least one of the wing flaps or the tail flap. Alternately, a vehicle may further include a programmable device operatively coupled to a navigational sensor and at least one actuator, the programmable device receiving an input signal from the navigational sensor and being capable of providing a control signal to the actuator according to the input signal.
In another alternate embodiment, a vehicle includes a hull having a pair of outwardly projecting at least partially arcuate wings, a first control surface attached to the hull that is adjustably positionable to provide at least partial control of at least a first dynamic characteristic of the vehicle, a first actuator coupled to the hull and to the first control surface to controllably adjust the position of the first control surface, a second control surface attached to the hull that is adjustably positionable to provide at least partial control of at least a second dynamic characteristic of the vehicle, and a second actuator coupled to the hull and to the second control surface to controllably adjust the position of the second control surface.
In still another embodiment, a vehicle includes a hull having a pair of outwardly projecting at least partially arcuate wings, adjustable control surface means attached to the hull for adjustably controlling a dynamic characteristic of the vehicle, and a plurality of actuators coupled to the hull and to the adjustable control surface means to controllably adjust the adjustable control surface means.